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Chapter 32 | Medical Applications of Nuclear Physics 1471
6. Which methods of radiation protection were used in the device shown in the first photo in Figure 32.35? Which were used in the situation shown in the second photo?
(a)
Figure 32.35 (a) This x-ray fluorescence machine is one of the thousands used in shoe stores to produce images of feet as a check on the fit of shoes. They are unshielded and remain on as long as the feet are in them, producing doses much greater than medical images. Children were fascinated with them. These machines were used in shoe stores until laws preventing such unwarranted radiation exposure were enacted in the 1950s. (credit: Andrew Kuchling ) (b) Now that we know the effects of exposure to radioactive material, safety is a priority. (credit: U.S. Navy)
7. What radioisotope could be a problem in homes built of cinder blocks made from uranium mine tailings? (This is true of homes and schools in certain regions near uranium mines.)
8. Are some types of cancer more sensitive to radiation than others? If so, what makes them more sensitive?
9. Suppose a person swallows some radioactive material by accident. What information is needed to be able to assess possible
damage?
32.3 Therapeutic Uses of Ionizing Radiation
10. Radiotherapy is more likely to be used to treat cancer in elderly patients than in young ones. Explain why. Why is radiotherapy used to treat young people at all?
32.4 Food Irradiation
11. Does food irradiation leave the food radioactive? To what extent is the food altered chemically for low and high doses in food irradiation?
12. Compare a low dose of radiation to a human with a low dose of radiation used in food treatment.
13. Suppose one food irradiation plant uses a source while another uses an equal activity of . Assuming equal
fractions of the rays from the sources are absorbed, why is more time needed to get the same dose using the source?
32.5 Fusion
14. Why does the fusion of light nuclei into heavier nuclei release energy?
15. Energy input is required to fuse medium-mass nuclei, such as iron or cobalt, into more massive nuclei. Explain why.
16. In considering potential fusion reactions, what is the advantage of the reaction over the reaction